Visual notification methods for candy-bar type cellphones

ABSTRACT

A wireless handheld communications device with a liquid crystal display, especially, a field sequential liquid crystal display, includes a visual notification for a powered up, inactive state. The visual notification is preferably through a light emitting diode that may be part of the backlighting system for the LCD or may be independent from the backlighting system. The waveforms, periodicity, color selection, and color sequencing may be customizable by one or both of the manufacturer and user.

RELATED APPLICATION

This is a U.S. continuation patent application related to U.S. patentapplication Ser. No. 10/940,977 filed on Sep. 15, 2004.

FIELD OF THE INVENTION

The present invention relates to the field of wireless communicationsdevices and, particularly, to visual notification methods for wirelesscommunications devices.

BACKGROUND

Wireless devices often use transmissive liquid crystal displays (LCDs).The transmissive LCDs are illuminated by a light source that usually islocated behind the LCD with respect to a user viewing the display.Powering the LCD and the light source is a power source, usually abattery. The battery life is most impacted when the LCD is ON. Thedisplay must be turned off when the wireless device is not being used soas to conserve battery life. Often, especially when a wireless devicehas been powered on and then unused for an extended period of time, thewireless device may appear to have been powered down while wastingbattery power. Thus, there is a need to provide notification to a userof the wireless device that power is on.

SUMMARY

This invention addresses the problem of notifying a user of a powered upwireless device without rapidly reducing battery power. The method alsooffers a customizable colour inactivity notification system. Inactivitynotification may be provided through a light source dedicated tonotification or a light source that illuminates the display that mayalso be used for notifications. The light source is preferably one ormore light emitting diodes.

Other aspects and features of the present invention will become apparentto those of ordinary skill in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of present invention will now be described by way of examplewith reference to attached figures, wherein:

FIG. 1 is a block diagram that illustrates pertinent components of awireless communications device that communicates within a wirelesscommunication network according to the present invention;

FIG. 2 is a more detailed diagram of a preferred wireless communicationsdevice of FIG. 1 according to the present invention;

FIG. 3 illustrates an embodiment of a backlit liquid crystal display ofthe present invention;

FIG. 4 illustrates an embodiment of the liquid crystal display andliquid crystal display controller of the present invention;

FIG. 5 illustrates a timing scheme for the light source and the displayscans;

FIG. 6 illustrates an embodiment of a section of the gate line driver;

FIG. 7 illustrates a general overview of the method of illuminating anLCD;

FIG. 8 illustrates further detail of an embodiment of the scanning forone colour within one frame;

FIG. 9 illustrates an embodiment of a method for providing anotification of the present invention;

FIG. 10 illustrates a notification waveform with a notification signalat a regular interval;

FIG. 11 illustrates a notification waveform with a non-uniform interval;

FIG. 12 illustrates another embodiment of a notification waveform with anon-uniform interval;

FIG. 13 illustrates a sinusoidal notification waveform; and

FIG. 14 illustrates a triangular waveform.

DETAILED DESCRIPTION

The present invention relates to a method and device, especially amobile station such as a handheld communications device, that practicesthe method for providing notification for a powered on, inactive device.Preferably, the display is a liquid crystal display (especially, a fieldsequential LCD-FS LCD) and the light source includes light emittingdiodes (LEDs) of different colours. The liquid crystal display may beoperated at a rate of 30 or more frames per second in which light ofsuccessive colours flash or pulse once per frame. The LEDs of the lightsource preferably will include red, green, and blue colours. Othercolour schemes, such as cyan, magenta, and yellow, are contemplated bythe present invention. Although the present invention is directed to aliquid crystal display per se, the preferred use of the LCD is in amobile station. Optionally, a light sensor may be used to vary thebrightness of a notification so as to optimize power consumption.

FIG. 1 is a block diagram of a communication system 100 that includes amobile station 102 that communicates through a wireless communicationnetwork. Mobile station 102 preferably includes a visual display 112, akeyboard 114, and perhaps one or more auxiliary user interfaces (UI)116, each of which is coupled to a controller 106. Controller 106 isalso coupled to radio frequency (RF) transceiver circuitry 108 and anantenna 110.

Typically, controller 106 is embodied as a central processing unit (CPU)which runs operating system software in a memory component (not shown).Controller 106 will normally control overall operation of mobile station102, whereas signal processing operations associated with communicationfunctions are typically performed in RF transceiver circuitry 108.Controller 106 interfaces with device display 112 to display receivedinformation, stored information, user inputs, and the like. Keyboard114, which may be a telephone type keypad or full alphanumeric keyboard,is normally provided for entering data for storage in mobile station102, information for transmission to network, a telephone number toplace a telephone call, commands to be executed on mobile station 102,and possibly other or different user inputs.

Mobile station 102 sends communication signals to and receivescommunication signals from the wireless network over a wireless link viaantenna 110. RF transceiver circuitry 108 performs functions similar tothose of a base station and a base station controller (BSC) (not shown),including, for example, modulation/demodulation and, possibly,encoding/decoding and encryption/decryption. It is also contemplatedthat RF transceiver circuitry 108 may perform certain functions inaddition to those performed by a BSC. It will be apparent to thoseskilled in art that RF transceiver circuitry 108 will be adapted toparticular wireless network or networks in which mobile station 102 isintended to operate.

Mobile station 102 includes a battery interface (IF) 134 for receivingone or more rechargeable batteries 132. Battery 132 provides electricalpower to electrical circuitry in mobile station 102, and battery IF 132provides for a mechanical and electrical connection for battery 132.Battery IF 132 is coupled to a regulator 136 which regulates power tothe device. When mobile station 102 is fully operational, an RFtransmitter of RF transceiver circuitry 108 is typically keyed or turnedon only when it is sending to network, and is otherwise turned off toconserve resources. Similarly, an RF receiver of RF transceivercircuitry 108 is typically periodically turned off to conserve poweruntil it is needed to receive signals or information (if at all) duringdesignated time periods.

Mobile station 102 operates using a Subscriber Identity Module (SIM) 140which is connected to or inserted in mobile station 102 at a SIMinterface (IF) 142. SIM 140 is one type of a conventional “smart card”used to identify an end user (or subscriber) of mobile station 102 andto personalize the device, among other things. Without SIM 140, themobile station terminal is not fully operational for communicationthrough the wireless network. By inserting SIM 140 into mobile station102, an end user can have access to any and all of his/her subscribedservices. SIM 140 generally includes a processor and memory for storinginformation. Since SIM 140 is coupled to SIM IF 142, it is coupled tocontroller 106 through communication lines 144. In order to identify thesubscriber, SIM 140 contains some user parameters such as anInternational Mobile Subscriber Identity (IMSI). An advantage of usingSIM 140 is that end users are not necessarily bound by any singlephysical mobile station. SIM 140 may store additional user informationfor the mobile station as well, including datebook (or calendar)information and recent call information.

Mobile station 102 may consist of a single unit, such as a datacommunication device, a multiple-function communication device with dataand voice communication capabilities, a personal digital assistant (PDA)enabled for wireless communication, or a computer incorporating aninternal modem. Alternatively, mobile station 102 may be amultiple-module unit comprising a plurality of separate components,including but in no way limited to a computer or other device connectedto a wireless modem. In particular, for example, in the mobile stationblock diagram of FIG. 1, RF transceiver circuitry 108 and antenna 110may be implemented as a radio modem unit that may be inserted into aport on a laptop computer. In this case, the laptop computer wouldinclude display 112, keyboard 114, one or more auxiliary UIs 116, andcontroller 106 embodied as the computer's CPU. It is also contemplatedthat a computer or other equipment not normally capable of wirelesscommunication may be adapted to connect to and effectively assumecontrol of RF transceiver circuitry 108 and antenna 110 of a single-unitdevice such as one of those described above. Such a mobile station 102may have a more particular implementation as described later in relationto mobile station 202 of FIG. 2.

FIG. 2 is a detailed block diagram of a preferred mobile station 202.Mobile station 202 is preferably a two-way communication device havingat least voice and advanced data communication capabilities, includingthe capability to communicate with other computer systems. Depending onthe functionality provided by mobile station 202, it may be referred toas a data messaging device, a two-way pager, a cellular telephone withdata messaging capabilities, a wireless Internet appliance, or a datacommunication device (with or without telephony capabilities). Mobilestation 202 may communicate with any one of a plurality of fixedtransceiver stations 200 within its geographic coverage area.

Mobile station 202 will normally incorporate a communication subsystem211, which includes a receiver, a transmitter, and associatedcomponents, such as one or more (preferably embedded or internal)antenna elements and, local oscillators (LOs), and a processing modulesuch as a digital signal processor (DSP) (all not shown). Communicationsubsystem 211 is analogous to RF transceiver circuitry 108 and antenna110 shown in FIG. 1. As will be apparent to those skilled in field ofcommunications, particular design of communication subsystem 211 dependson the communication network in which mobile station 202 is intended tooperate.

Network access is associated with a subscriber or user of mobile station202 and therefore mobile station 202 requires a Subscriber IdentityModule or “SIM” card 262 to be inserted in a SIM IF 264 in order tooperate in the network. SIM 262 includes those features described inrelation to FIG. 1. Mobile station 202 is a battery-powered device so italso includes a battery IF 254 for receiving one or more rechargeablebatteries 256. Such a battery 256 provides electrical power to most, ifnot all, electrical circuitry in mobile station 202, and battery IF 254provides for a mechanical and electrical connection for it. The batteryIF 254 is coupled to a regulator (not shown) which provides power V+toall of the circuitry.

Mobile station 202 includes a processor 238 (which is one implementationof controller 106 of FIG. 1) which controls overall operation of mobilestation 202. Communication functions, including at least data and voicecommunications, are performed through communication subsystem 211.Processor 238 may be a microprocessor integrated circuit, a processingcore in an area of an integrated circuit, or the like. Processor 238also interacts with additional device subsystems such as a display 222,a flash memory 224, a random access memory (RAM) 226, auxiliaryinput/output (I/O) subsystems 228, a serial port 230, a keyboard 232, aspeaker 234, a microphone 236, a short-range communications subsystem240, and any other device subsystems generally designated at 242. Someof the subsystems shown in FIG. 2 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 232 and display222, for example, may be used for both communication-related functions,such as entering a text message for transmission over a communicationnetwork, and device-resident functions such as a calculator or tasklist. Operating system software used by processor 238 is preferablystored in a persistent store such as flash memory 224, which mayalternatively be a read-only memory (ROM) or similar storage element(not shown). Those skilled in the art will appreciate that the operatingsystem, specific device applications, or parts thereof, may betemporarily loaded into a volatile store such as RAM 226.

Processor 238, in addition to its operating system functions, preferablyenables execution of software applications on mobile station 202. Apredetermined set of applications which control basic device operations,including at least data and voice communication applications, willnormally be installed on mobile station 202 during its manufacture. Apreferred application that may be loaded onto mobile station 202 may bea personal information manager (PIM) application having the ability toorganize and manage data items relating to the user such as, but notlimited to, instant messaging (IM), e-mail, calendar events, voicemails, appointments, and task items. Naturally, one or more memorystores are available on mobile station 202 and SIM 262 to facilitatestorage of PIM data items and other information.

The PIM application preferably has the ability to send and receive dataitems via the wireless network. In a preferred embodiment, PIM dataitems are seamlessly integrated, synchronized, and updated via thewireless network, with the mobile station user's corresponding dataitems stored and/or associated with a host computer system therebycreating a mirrored host computer on mobile station 202 with respect tosuch items. This is especially advantageous where the host computersystem is the mobile station user's office computer system. Additionalapplications may also be loaded onto mobile station 202 through network200, an auxiliary I/O subsystem 228, serial port 230, short-rangecommunications subsystem 240, or any other suitable subsystem 242, andinstalled by a user in RAM 226 or preferably a non-volatile store (notshown) for execution by processor 238. Such flexibility in applicationinstallation increases the functionality of mobile station 202 and mayprovide enhanced on-device functions, communication-related functions,or both. For example, secure communication applications may enableelectronic commerce functions and other such financial transactions tobe performed using mobile station 202.

In a data communication mode, a received signal such as a text message,an e-mail message, or web page download will be processed bycommunication subsystem 211 and input to processor 238. Processor 238will preferably further process the signal for output to display 222, toauxiliary I/O device 228 or both as described further herein below withreference to FIGS. 3 and 4. A user of mobile station 202 may alsocompose data items, such as e-mail messages, for example, using keyboard232 in conjunction with display 222 and possibly auxiliary I/O device228. Keyboard 232 is preferably a complete alphanumeric keyboard and/ortelephone-type keypad. These composed items may be transmitted over acommunication network through communication subsystem 211.

For voice communications, the overall operation of mobile station 202 issubstantially similar, except that the received signals would be outputto speaker 234 and signals for transmission would be generated bymicrophone 236. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on mobilestation 202. Although voice or audio signal output is preferablyaccomplished primarily through speaker 234, display 222 may also be usedto provide an indication of the identity of a calling party, duration ofa voice call, or other voice call related information, as some examples.

Serial port 230 in FIG.2 is normally implemented in a personal digitalassistant (PDA)-type communication device for which synchronization witha user's desktop computer is a desirable, albeit optional, component.Serial port 230 enables a user to set preferences through an externaldevice or software application and extends the capabilities of mobilestation 202 by providing for information or software downloads to mobilestation 202 other than through a wireless communication network. Thealternate download path may, for example, be used to load an encryptionkey onto mobile station 202 through a direct and thus reliable andtrusted connection to thereby provide secure device communication.

Short-range communications subsystem 240 of FIG. 2 is an additionaloptional component which provides for communication between mobilestation 202 and different systems or devices, which need not necessarilybe similar devices. For example, subsystem 240 may include an infrareddevice and associated circuits and components, or a Bluetooth™communication module to provide for communication with similarly-enabledsystems and devices. Bluetooth™ is a registered trademark of BluetoothSIG, Inc.

In accordance with an embodiment of the invention, mobile station 202 isa multi-tasking handheld wireless communications device configured forsending and receiving data items and for making and receiving voicecalls. To provide a user-friendly environment to control the operationof mobile station 202, an operating system resident on station 202 (notshown) provides a GUI having a main screen and a plurality ofsub-screens navigable from the main screen.

The liquid crystal display cell 222 is shown in greater detail in FIG. 3in which a light source formed from multiple LEDs 322, 324, 326 is usedas a backlight. LCD controller 316 provides a voltage to the commonelectrode(s) 308 and the active elements 310 of the active matrix. Theactive elements are preferably thin film transistors. The commonelectrode(s) 308 and active elements are supported on substrates 306 and312, respectively. The LCD preferably contains a brightness enhancingfilm or layer 304 to optimize the distribution of light for a viewer. Asthe preferred liquid crystal material is super twisted nematic,polarizers 302 and 314 are used. The LCD controller 316 sets the pixelgrey scale of the LCD. An optional processor 318 may coordinatesynchronization of the LCD controller 316 with the light sourcecontroller 320. Preferably, the LCD controller 316 and the processor 318are integrated into a single device 317, which may simply be referred toas an LCD controller having the capability of controlling a light sourcecontroller 320. The light source may be implemented by using red, green,and blue LEDs 322, 324, 326. In a specific embodiment, four green, fourred, and two blue LEDs are used to provide full colour and/or black andwhite display. Other colour combinations are contemplated. The LEDcontroller 320 may sequence the three colours or may simultaneouslyenergized LEDs of all of the colours and terminate power to the LEDssimultaneously. Other combinations of LEDs are contemplated. The lightguide 328 may have a tapered block construction and may haveapproximately a trapezoidal form to more evenly distribute the lightinto the LCD. The light guide may also have uneven areas 330, 332 thatscatter the light so as to avoid shadowing effects in the LCD image.Although uneven area 330 is shown to project out from the surface of thelight guide 328 and uneven area 332 is shown to project inward to thesurface ofthe light guide 328, the uneven areas may be arrangeddifferently so long as the arrangement effectively scatters the lightfrom the LEDs 322, 324, 326. The uneven areas may be abraded, molded,corrugated, chemically etched, or the like. Preferably, to maximize theutilization of light, the LEDs 322, 324, 326 and the light guide 328 arepartially enclosed by a reflector such that the only opening is fullybounded by the light transmissive area of the LCD.

FIG. 4 illustrates an embodiment of the LCD controller 402 and LCD 430for the method. The LED controller may be internally adapted to providea sequence of lights each centered on a specific wavelength according tothe LEDs energized, followed by light generated simultaneously from allLEDs or at least two LEDs generating light centered on two or moredifferent wavelengths. In FIG. 4, in synchronization with the LEDcontroller, the LCD controller 402 creates a grey scale pattern for eachlight centred on a specific wavelength according to column driver 440(source driver) according to data and control signals 410 and rowselectors 450 (gate driver) from a data bit line and a LOAD LINE clockin a X-Y matrix arrangement. For a red light pattern, only pixelsselectable by the column driver 440 may be set to a transmissive stateto provide a desired pattern. Pixels that do not have a red component oflight are turned off. For green and blue light patterns, similarprocedures are followed. When all red, green, and blue colours aretransmitted through a given pixel, that pixel may have a white orwhitish appearance because of the blending of the three primary coloursperceived by a viewer. Advantages in using the light source to determinecolours include elimination of a colour filter layer, thus enhancingbrightness of the display by removing a light absorbing layer, andincreasing the resolution as only one pixel is needed to provide fullcolour instead of separate red, green, and blue pixels. The size of apixel is allowed to increase while resolution is improved; in otherwords, using the light source and not the LCD to determine colouroptimizes LCD substrate real estate usage by increasing pixel size andimproving the aperture ratio of a pixel.

FIG. 5 illustrates a colour only mode in which either the entire displayscreen is in colour or the non-colour portion of the display screen isin the off state. In operation, pixel grey scale is achieved throughpulses written to a pixel during scanning. Each colour frame 502 isdivided into three parts (or fields) 504, 506, 508 for the three coloursin full colour mode. Each pixel to be illuminated by a specific colourof light achieves a grey scale value from a pulse pattern into thesource of the thin film transistor providing charge to the pixel. Thepulse pattern (i.e., colour scans) includes multiple high and/or lowpulses for each pixel. One pulse is applied to each colour pixel duringa scan of the colour region that includes the colour pixel. During thecolour region scan (or sweep) 532, the actual scanning occupies most ofthe time allotted 530 for a given colour. It is the successive scans ofthe colour pixels (e.g., red, then green, then blue) during a frame thatestablishes a full colour grey scale value. A smaller portion of thetime allotted in a scan period is idle time 534. During most of the scanperiod, the light source is turned off 514. In alternative embodiments,the light source may remain on for most or all ofthe scan period and/orthe actual scanning may occupy a different portion of the time allottedfor a given colour. Once the final grey scale value for a row or line ofpixels is fairly well established, the light source (e.g., lightemitting diode) is turned on 512. In some embodiments, during the lightsource turn on time, the common electrode of the display is invertedfrom a first voltage bias level 522 to a second voltage bias level 524to prevent charge buildup in the liquid crystal that would degradeperformance and damage the display. The inversion of the commonelectrode voltage occurs for each colour for each frame. Thus, for ared, green, and blue pixel LCD, the common electrode voltage is invertedthree times. Other inversion modes are contemplated such as lineinversion and pixel inversion. In line inversion, a given line may bealternately supplied through the source driver with voltages from afirst set of a polarity and then supplied with voltages from a secondset of a polarity opposite to that of the first set; that is, anon-inverting pair of voltages may be applied and an inverting pair ofvoltages may later be applied. In pixel inversion, alternate columns maybe supplied for each row with voltage sets of opposing polarities.

FIG. 6 represents a more specific embodiment. An output shift register(e.g., serial in/parallel out shift register) may be used for scanningthe display screen. The shift register contains initialization valuesfor the gate shift register. It preferably contains a one-hot encodingof the starting line number of display screen. (As used in anembodiment, one-hot encoding refers to a single active bit that isshifted through the shift register such that only one line at a time ofpixels is written to and read from the source driver.) The shiftregister is loaded and then used to sweep the display. A LINE CLOCK rateis relatively high; for example, a 10 MHz clock rate may be used. Thestorage elements may be latches 618, 626 that latch data on the risingor falling edges of a clock, D type flip flops, or the like. A counter602 may be used to hold the number of lines in the display screen.

FIG. 7 illustrates an overview of the embodiment of a methodcorresponding to the display scanning system. In the general method,initialization occurs 704 (e.g., registers are initialized) and thethree colour fields are cycled through 706-710 through successive scansduring a frame, Mono regions (i.e., regions only permitting a single ONcolour and a different single OFF colour with no grey scale used) may beimplemented.

FIG. 8 illustrates a more detailed embodiment of a scan for a field. Thegate line driver is shifted once 804. The load pattern is deasserted806. A new source pattern is loaded 807. The source lines on the displaymatrix are driven 808. The line count is reduced by one 810. As long asthe counter does not expire (e.g., the line count remains greater thanzero in a count down mode) 812, scanning resumes at step 804.

FIG. 9 illustrates an embodiment of a notification method. Anotification timer is cleared 902. If a triggering event occurs 904, thenotification timer is cleared again 902. The triggering event may be thepressing of a key, moving a thumb wheel, physically moving the device,and the like. If no triggering event occurs 904, the timer increments906 the timer count value. If the timer count value exceeds a threshold908, the device enters notification mode 910. In notification mode, avisual notification occurs to alert the user to the power on, inactivestate of the device. In one embodiment, there is a light emitting diode(LED) notification “heartbeat” in which the notification LED flashesregularly or irregularly to indicate the device is still powered up. TheLED colour for an inactive, powered on state may be selected to bedifferent from an LED colour for a message notification. In anotherembodiment, part or all of the LCD backlight (e.g., one or more but lessthan all the LEDs of the backlight) may be used to provide a largevisual area.

Various embodiments of the inactive, powered up state notificationsignal may be implemented. FIG. 10 shows a waveform 1002, 1006, 1010that occurs at a uniform interval 1004, 1008. FIG. 11 shows a waveform1102, 1106, 1110, 1114 that occurs at other than a uniform interval. Anon-uniform interval may be irregular or vary between two or more fixedperiods of time. LED brightness may be ramped up and ramped down toprovide a type of “breathing” or “heartbeat” effect to make flashingless harsh—a benefit in dark or dimly lit conditions. The ramping effectmay be creation through switching and voltage division circuitry. FIG.12 shows a waveform 1202, 1206, 1210, 1214 that occurs more nearly as aheartbeat as found on a typical electrocardiogram. In FIG. 12, the firstpulse 1202 is greater in amplitude than a companion second pulse 1206.The amplitude ratio between the first and second pulses 1202 and 1206(or, 1210 and 1214) may be made adjustable and could range from 1:1 to6:1. For example, the first pulse's amplitude might be twice or one anda half times that of the second pulse's amplitude. The first and secondpulse may be joined without any interval between them. In an exemplaryembodiment, the frame period may be 33.33 milliseconds in which thefirst and second pulses each last 0.65 milliseconds. FIG. 13 shows asinusoidal waveform that permits a user to see a relatively gradualincrease in intensity from OFF 1302 through steps 1304, 1306, and 1308,and a relatively gradual decrease through steps 1310, 1312, and 1314 tothe OFF state 1316. FIG. 14 presents a triangular waveform 1404 betweenoff states 1402 and 1406. Aside from sinusoidal and triangularwaveforms, square waveforms and other waveforms may be used.

Notification may be provided within a variety of other ways. Since morethan one colour of LCD backlight is available in field sequential typedisplays, the colour may be alternated. For example, the colour mayflash red for a period of time, then switch to blue and back again. Or,two or more colours may be combined to provide blended colours such asyellow or orange. Graphics, such as “INACTIVE DEVICE” or “PLEASE POWERDOWN,” may be used. Alternatively, a user may customize the displaycolour for this type of “heartbeat.” This may be especially useful forthose people who are more responsive to certain colours than to others;for example, a user with red-green colour blindness. Using only one LEDat a time would save power and would also result in a lowered brightnesslevel compared to normal use of the device because only one of the threecolours would be used.

The interval settings and waveform shapes and behaviors may be set by amanufacturer and/or may be settable by a user to provide a customizedinactive device notification display. Through menu selections, a usermay be able to vary the inactive period length to delay or quicken thepresentation of inactive device notification. A menu may permit blendedcolour selection according to saturation and hue and may permit asequencing of different colours. Enhanced pulsation or blinking featuresmay be used, including using all or a portion of the LCD screen as ablank screen that changes colour. The LCD screen may present blinkingand/or animated graphics and/or text. The above-described embodiments ofthe present application are intended to be examples only. Those of skillin the art may effect alterations, modifications and variations to theparticular embodiments without departing from the scope of theapplication. The invention described herein in the recited claimsintends to cover and embrace all suitable changes in technology.

The invention claimed is:
 1. A method of indicating inactivity of apowered on, inactive electronic device having a display, the displayhaving a backlight comprising multiple light emitting diodes (LEDs), themethod comprising: tracking an inactivity time for the electronicdevice; comparing the inactivity time against a threshold; if theinactivity time exceeds the threshold, activating a visual notificationon the electronic device to indicate inactivity of the electronic deviceto the user by using at least one LED of the backlight, but less thanall of the LEDs of the backlight in a flashing pattern; andsynchronizing the display to set only pixels in the display that have acolour component corresponding to a colour of an LED that is beingactivated in the flashing pattern to a transmissive state.
 2. The methodof claim 1, wherein the flashing pattern is a pulsing light signalgenerated by one or more of but less than all of the LEDs.
 3. The methodof claim 1, wherein the LEDs emit light with a colour from the groupconsisting of red, green, and blue.
 4. The method of claim 1, whereinthe LEDs emit light with a blended colour comprising a combination oftwo or more colours from the group comprising red, green, and blue. 5.The method of claim 1, wherein the flashing pattern has an intensitycycle defined by any of a waveform, a square wave, a sinusoidal wave ora triangular wave.
 6. The method of claim 1, wherein the flashingpattern is activated on a regular interval.
 7. The method of claim 1,wherein the flashing pattern is activated on an irregular interval. 8.The method of claim 1, wherein the flashing pattern comprises a signalhaving a first pulse occurring at a first time and a second pulseoccurring at a second time and the signal is repeated at a regularinterval.
 9. The method of claim 8, wherein the first pulse and thesecond pulse have the same amplitude in intensity.
 10. The method ofclaim 8, wherein the first pulse and the second pulse have differentamplitudes in intensity.
 11. The method of claim 10, wherein theamplitude of the first pulse is about twice as great as the amplitude ofthe second pulse.
 12. The method of claim 1, further comprisingsynchronizing the display to set pixels in the display that do not havea colour component corresponding to the colour of the LED that is beingactivated in the flashing pattern to an off state.
 13. The method ofclaim 1, further comprising inverting a common electrode of a lightsource in the display corresponding to a colour of an LED that is beingactivated in the flashing pattern from a first voltage bias level to asecond voltage bias level.
 14. An electronic device, comprising: aliquid crystal display; a backlight for the liquid crystal displaycomprising multiple light emitting diodes (LEDs); a processor forcontrolling the liquid crystal display; a keypad for providing input tothe processor; and a module to monitor any inactivity time of theelectronic device, the module being configured to activate a visualnotification on the electronic device of an inactive state of theelectronic device with the liquid crystal display by using at least oneLED of the backlight but less than all of the LEDs in a flashing patternand by synchronizing the display to set only pixels in the display thathave a colour component corresponding to a colour of an LED that isbeing activated in the flashing pattern to a transmissive state.
 15. Theelectronic device of claim 14, wherein the liquid crystal display is afield sequential liquid crystal display.
 16. The electronic device ofclaim 14, wherein the LEDs include red, green and blue light emittingdiodes which are selectively activated to provide a colour feature tothe visual notification.
 17. The electronic device of claim 14, whereinthe visual notification produced by the LEDs is a pulsing light signalhaving an intensity cycle defined by any of a waveform, a square wave, asinusoidal wave or a triangular wave.
 18. The electronic device of claim17, wherein: the pulsing light signal has a first pulse occurring at afirst time and a second pulse signal occurring at a second time; and thepulsing light signal is repeated at a regular interval.
 19. Theelectronic device of claim 18, wherein the first pulse and the secondpulse have the same amplitude in intensity.
 20. The electronic device ofclaim 18, wherein the first pulse and the second pulse have differentamplitudes in intensity.